Multi-position wafer switch with fastening means and short-circuiting contact structure



Oct. 19, 1965 K. c. ALLISON 3,213,211

MULTI-POSITION WAFER 5 CH H FASTENING MEANS AND SHORT-GIRCUIT CO CTSTRUCTURE Filed Sept. 4, 1962 3 Sheets-Sheet l O HHHHHI 56HHHIIHIIHHIIIH O II Q) 2 0 OO GO G O Q 0 ding} 2 llll O G 30 O O 28 Q GO IHH /6 20 O y 57 Q Q) /0 FIG. 2

INVENTOR KENNETH C. ALLISON ATTORNEY 0 FIG. I.

Oct. 19, 1965 K. c. ALLISON 3,2 211 MULTI- ION WAFER SWITCH WITHFASTENING MEANS AN ORT-CIRCUITING CONTACT STRUCTURE Filed Sept. 4, 196 3Sheets-Sheet 2 INVENTOR KENNETH C. ALLISON FIG 6 BYflQW'WgM ATTORNEYOct. 19, 1965 K c, ALLISON 3,213,211

MULTI-POSITION WAFER SWITCH WITH FASTENING MEANS AND SHORT-CIRCUITINGCONTACT STRUCTURE Filed Sept. 4, 1962 3 Sheets-Sheet 3 INVENTOR KENNETHC. ALLISON BY gl 13. M

AT TOR NEY United States Patent MULTI-PGSITION WAFER SWITCH WITH FASTEN-ING MEANS AND SHURT-CIRCUITING CON- TACT STRUCTURE Kenneth C. Allison,Crystai Lake, IlL, assignor to CTS Corporation, Elkhart, Ind., acorporation of Indiana Filed Sept. 4, 1962, Ser. No. 221,096 Claims.(Cl. 200-11) This invention relates to multi-position electric switchesgenerally, and in particular, to improving the means for anchoring thestationary and movable contacts to the bodies of insulating materialwhich form the stator and rotor of the switch.

One persistent problem has always confronted rotary switch designershowto securely anchor the stationary contacts to the stator and the bladeto the rotor in a manner that will not be prohibitively expensive butwhich will prevent the contacts from moving relative to the member towhich they are attached, and which will not prevent or restrict themovements necessary to the operation of the switch.

The switch contact members are most commonly attached by eyelets orhollow rivets. This is the simplest and most economical method. Rivets,however, are unable to hold the contacts aligned properly. In otherwords, when the moving rotor blades engage the stationary contacts, theytend to rotate around the rivet in the same direction as the rotorblades are moving. Obviously, such movement should be prevented.

This is commonly done by having the lower half of the contact jaw extendinto a slot formed in the stator body. This arrangement requires thespring arm of the lower contact jaw to be shorter than the spring arm ofthe upper jaw which combines with the resistance to movement offered bythe slot to force the upper jaw to do most of the flexing necessary toaccommodate the rotor blade. This shortens the life of the contact,causes uneven contact wear, and generally increases the torque necessaryto move the rotor blade from position to position.

Accordingly, it is an object of this invention to provide means forattaching the contacts to a rotary wafer switch which will eliminaterelative movement of the contacts with respect to the body of insulatingmaterial to which they are attached.

It is a further object of this invention to provide means for anchoringthe movable contact blades carried by the rotor which will support thecontacts at the maximum possible distance from the center of the rotor.

It is an additional feature of this invention to provide a contact forthe stator which will resiliently engage the stator with sufficientforce to prevent relative movement of the contact but which will notdamage the stator.

It is also an object of this invention to provide a switch withsymmetrically shaped stationary contacts attached to the switch statorso that both jaws are free to move equal distances.

It is an additional object and an important feature of the invention toprovide a switch which is so designed that misalignment between thestationary contacts and the rotor blades is eliminated.

It is also an object of this invention to provide a 3,213,211 PatentedOct. 19, 1965 rotary wafer switch of generally simplified and improveddesign.

The invention comprises a stator and a rotor, each being a body ofinsulating material with attached electrically conductive contacts. Thestator body is T- shaped in cross section, having a thick peripheralsection and a relatively thin inner section. The inner section supportsthe rotor whereas the peripheral section supports the contacts which canbe attached to both sides. The peripheral section also is provided withribs or abutments between which the contacts are located. The contactsare provided with a curved section which engages the ribs or abutmentsat the outer periphery of the stator for aligning the contacts withrespect to the ribs and for preventing rotation of the contacts aroundthe attaching rivet. The contact jaws do not engage the ribs on thestator so both are free to flex equal amounts to accommodate the rotorblades.

The rotor is rotatably supported by the stator and comprises a body ofinsulating material with a plurality of metal fingers embedded therein.The fingers support a flat metal member from which the desired bladingis formed. Being firmly embedded in the body of the rotor the blades aresecurely held against rotation with respect to the body of insulatingmaterial. The blades are also securely held against movement out of theplane of the stationary contacts since the rotor body supports the bladethe maximum possible distance toward the stationary contacts.

Also since the rotor blading is formed after it is attached to therotor, various individual blades are located on the rotor veryaccurately. In fact, the blades are located within the accuracy of thetooling which forms them. This system is obviously much superior to theheretofore used system of forming the rotor blades prior to their beingattached to the rotor body. The rotor blades can now be very accuratelypositioned in both the horizontal and vertical planes and held inposition throughout the life of the switch since no relative motion canoccur between the rotor blades and the rotor body.

The invention will now be described in detail in connection with theaccompanying drawings in which:

FIGURE 1 is a plan view of a rotary wafer switch constructed inaccordance with this invention;

FIGURE 2 is a cross-sectional view of the switch of FIGURE 1 taken alongline 2-2;

FIGURE 3 is an isometric view of a typical stationary contact showinghow the section adjacent the rivet hole is curved;

FIGURE 4 is a sectional view illustrating the relationship of the curvedsection of the stationary contact and the stator prior to riveting;

FIGURE 5 illustrates the position of the curved section after thestationary contact is riveted to the stator;

FIGURE 6 is an enlarged top view of a stationary contact in positionbetween two ribs;

FIGURE 7 is a portion of a metal strip which has had portions cut awaypreparatory to having the rotor body molded thereto;

FIGURE 8 shows the metal strip of FIGURE 7 after the molding operation;and

FIGURE 9 illustrates another method of anchoring the stationary contactsagainst rotation.

The switch consists of a stator section It) and a rotor section 12. Therotor section has an opening 13 to receive a flat sided shaft (notshown) by which rotation is imparted to the rotor.

The stator section comprises an annular body of insulating material witha plurality of contacts attached thereto. The annular body is T-shapedin cross-section having a relatively thick peripheral section 14 and .arelatively thin inner section 15. The inner section serves to insulatethe contacts mounted on one side of the stator from those mounted on theother and to rota-tably support the rotor. Mounted on both sides of therelatively thick peripheral section 14 of the stator is a plurality ofcontacts indicated generally by the number 1 1 which are identicalexcept for their length. For example, the contact 16 extends inwardlytoward the rotor further than does the contact 17 which is a well knownexpedient to vary the switch circuitry.

The contacts 11 are attached to the stator body by means of hollowrivets or eyelets 18 which extend through openings 1 9 in the contactand openings 20 in the stator body as illustrated in FIGURE 2. Eachcontact is located between two ribs or abutments .22, a plurality ofwhich are provided on both sides of the thick peripheral section of thestator body. Each rib or abutment is provided with a wedge-shaped backsection 125 so that the distance between them is less .at the outerperiphery than it is at the inner edge of the section 14. In the switchillustrated, these ribs or abutments are equally spaced and arranged toextend radially from the center of the switch. This is not necessary forthe practice of the invention as the ribs could extend across the statorat any angle commensurate with good switch design.

The openings 20 which are provided in the stator for the eyelets :18 arelocated equidistant between each pair of ribs -22 so that a contact canbe mounted between any pair of ribs on either side of the stator. In thestator illustrated in the drawings, the width of the ribs is such thatcontacts cannot be placed between adjacent pairs of ribs on the sameside of the stator without reducing the width of the contact jaws.Generally, it is better to have contact jaws as wide as possible tomaintain the contact pressure as large as possible. Rather than reducethe width of the jaws the ribs 22 are made as narrow as possible toprovide as many locations for contacts as can be conveniently arrangedon the stator. On the switch stator illustrated on the drawings, theribs are spaced so that there are 22 locations for contacts on each sideof the stator. Twenty-four spaces would be available except that somespace must be provided for mounting holes 23 and 24.

Since contacts cannot be placed in adjacent spaces as discussed above,the maximum number of contacts which can be attached is 12 on one sideand 10 on the other for a total of 22. If it is desired to electricallyconnect contacts on opposite sides of the stator, the number will varyaccordingly. Contacts on opposite sides of the stator can beelectrically connected by means of the eyelet or rivet which is used toattach both contacts to the stator.

The contacts 1 1 are conventionally shaped. Each is formed from a singlestrip of metal bent back on itself. Each has contact jaws 28 and 29,opening '19 to receive the mounting eyelet or rivet, and the opening 30through which a wire lead can be passed when the switch is connected inan electric circuit. The contact is shown in FIGURE 3 as it appearsbefore being attached to the stator. 'When attached the two halves areforced together as shown in FIGURE 2. This forces the contact jaws 28and 29 into engagement so that they will tightly grip the rotor blade 31for good electrical contact.

Usually the portion of the contacts from the contact jaws out to theterminal end are flattened when they are attached to the stator. Thestationary contacts of this invention, however, are constructed so thatthe solder terminal section will not be completely flattened.

As shown in FIGURES 3, 4, and 5, each half of the contact has oppositelycurved sections 44 and 45 located just back of the rivet hole 19. Thewidth of the contact at this point is such that when placed in positionbetween the ribs, there will be ample clearance. This allows thecontacts to be positioned easily during assembly. When the contact isriveted to the stator body however, the width of the curved sectionswill increase as they are flattened by the riveting operation until theyengage the ribs on each side. Actually only the section which happens tobe next to the stator will engage the ribs since it will :be flattenedmore than the other. When this section engages the ribs, (section 45 asshown in FIGURE 5) the contact will be forced into alignment with theribs. In other words if the contact is out of alignment when initiallyinstalled which is generally the case, one side of the curved sectionwill engage the rib and rotate the contact into position during theriveting operation since it will inherently seek to exert an equalamount of force on each rib. These curved sections then combine with theribs to provide an automatic method of aligning the contacts duringassembly. In this way, the contacts can be dropped into position withoutregard to their alignment which greatly facilitates the mass productionof these stators.

After the curved section has engaged both ribs thus forcing the contactinto alignment, it will begin to resist further flattening since to doso it must cut into the ribs. The width ot the contact is not such thateven if it were forced completely flat it would out very deep into theribs, however, the curved sections are spaced from the rivet far enoughto allow some curvature to remain after the riveting operation iscompleted. This allows the curved section to engage the ribs resilientlyso that only a given amount of force will be exerted on the ribs afterwhich the curved section will simply be flattened no further. This is animportant feature since there is a danger that the contact could exertenough force to shear the ribs off the stator body if they werecompletely flattened particularly if a structurally weak or brittleplastic is used to form the body, as is sometimes the case.

Another feature of this invention is the use of two oppositely curvedsurfaces 44 and 45 making line contact with each other. Since the forceflattening these sections is transmitted to the bottom section throughthe upper section the fact that the two sections make line contactallows the bottom section to freely adjust to its proper positionbetween the ribs 22 without having to overcome izny extraneoushorizontal components of the flattening orce.

Once in position between the ribs, the contact 11 is accurately alignedwith respect to the stator and securely held against movement by therivet or eyelet 18 and the curved section 45 in engagement with the ribs22 on each side of the contact. It is advantageous to have the curvedsection as far away from the rivet as possible to increase the momentarm resisting rotation and to get the best possible spring action fromthe curved sections 44 and 45. It is also important that the means usedto resist rotation of the contact be located on the opposite side of thecontact from the contact jaws. This leaves the contact jaws completelyfree to flex and allows them to be identically shaped so that they willflex equal amounts.

If the stator is made from a fairly soft material and the abutments orribs are not needed for locating or insulating purposes, the contactscan be anchored against rotation in the manner illustrated in FIGURE 9.No change need be made in the configuration of the contacts. The curvedsections 44 and 45 are so curved that they inherently provide the sharpedges 46 and 47. These edges are positioned so that when the contact isattached the downward force of the riveting operation will tend to forcethese edges into the body of the stator. If the stator is made from arelatively soft material, they will 5 be embedded in the stator to suchan extent that they will effectively hold the contact against rotationaround the unit.

Here, as is the case when the contact is located between ribs, thecurved sections are not flattened by the riveting operation. This allowsthese sections to resiliently hold the edges 46 and 47 in engagementwith the stator body. This resilient force also continuously exerts anupward force on the rivet thus preventing any looseness from developingbetween the contact and the rivet and the edges 46 and 47 and thestator.

The rotor for the switch comprises a body of insulating material whichsupports one or more flat electrically conductive blades. The switchillustrated has stationary contacts on both sides of the stator so thatrotor must also be equipped with blades on each side of the stator.

The rotor itself is made in two sections 32 and 33. The two sections areidentical and are combined to form the rotor by simply turning onesection over so that the top side of each is facing outwardly from theswitch. The blading of each section is different, of course, since thecontacts in one side must be at least 15 in advance of the other. It isthe configuration of the body of insulation which is the same. Eachrotor section is formed by molding a body of insulating material arounda plurality of fingers formed in a metal strip. FIGURE 7 illustrates themetal strip preparatory to having the insulating material moldedthereto. A group of perforations generally indicated by the numbers 51,52, 53 and 54 are formed in a circular pattern in the strip. Theseperforations provide fingers which are embedded in the bodies ofinsulating material. These fingers then support the blading which isformed from the metal strip adjacent the periphery of the body ofinsulating material. The fingers are embedded by molding the body ofinsulating around them. This is done before the blading is formed. Themetal strip with the rotor body molded thereon is shown in FIGURE 8. Thedotted lines indicate a typical rotor blade pattern. In fact it is thesame pattern as that shown in the switch of FIGURE 1.

This method of forming the rotor blading provides great flexibility inthe manufacture of rotary switches. Simply by arranging the cutting diesproperly practically any desired blading arrangement can be accuratelyand economically mass produced. In addition, the blades are securelyheld by the rotor body the maximum possible distance from the center ofthe rotor. This allows thinner more flexible metal to be used for theblading which reduces the distance the contact jaws on the stationarycontacts are flexed, greatly lengthening their life.

This type rotor also insures that the blading is all in the samehorizontal plane which eliminates variation in contact pressure. Thisalso lengthens the life of the switch and in addition produces a betterperforming switch.

The rotor is assembled in the manner shown in FIG- URE 2 with thesections 32 and 33 on opposite sides of the thin inner section 15 of thestator. Each section is provided with a groove 55 which engages thesection 15 and acts as the bearing for the rotor. The two sections areheld together on the stator by rivets 56 and 57 which extend throughopenings 58 and 59 provided in both sections.

If a single sided rotary switch is desired, no change in the basicstructure would be required. Stationary contacts would be placed on onlyone side of the stator, of course, and the rotor would consist of thesame two sections except that one section would have no metal inserts toprovide blading.

While there has been illustrated and described what is at presentconsidered to be a preferred embodiment of the present invention and asingle modification thereof, it will be appreciated that numerouschanges and modifications are likely to occur to those skilled in theart,

6 and it is intended in the appended claims to cover all those changesand modifications which fall within the true spirit and scope of thepresent invention.

The invention claimed is:

1. In a multi-position electric switch, the combination of a first andsecond cooperating relatively movable contact carriers of insulatingmaterial, a plurality of contact members arranged in a row and fixedlysecured to opposite sides of the first contact carrier; a pair ofsymmetrical contact jaws integrally secured to each of the contactmembers and extending toward the outer edge of the second contactcarrier; the second contact carrier comprising a pair of insulatingmembers disposed on opposite sides of the first contact carrier; agroove provided in the second contact carrier receiving and guiding aportion of the first contact carrier cooperating therewith upon relativemovement between the first and second contact carriers; a pair of commoncontacts, each of the insulating members being molded to one of thecommon contacts, each of the common contacts lying in a plane interposedbetween the contact jaws of the contact members associated therewith andmoving relative to the contact members in a path to be selectivelyengageable with the contact jaws as the switch is actuated to connectelectrically the individual contact members with the common contacts.

2. In a multi-position electric switch, the combination of a first andsecond cooperating relatively movable contact carriers of insulatingmaterial; a plurality of spaced ribs integrally secured to the firstcontact carrier along the outer edge thereof; a plurality of contactmembers arranged in a row and disposed between the spaced ribs, each ofthe contact members being provided with a laterally disposed curvedportion embedded in the portion of the rib adjacent to the outer edge ofthe first contact carrier, the portion of each of the ribs adjacent tothe outer edge of the first carrier being wedge-shaped so as to providea slot having a smaller width at the outer periphery of the firstcarrier and a larger width at the other end of the slot to position thecontact members between the ribs; a pair of symmetrical jaws integrallysecured to each of the contact members; a common contact; and supportingmeans integral with the common contact fixedly secured to the secondcontact carrier, the common contact lying in a plane interposed betweeneach of the pair of symmetrical jaws and moving relative to the firstcarrier in a path to be selectively engageable with the symmetrical jawsof each of the contact members as the switch is actuated to connect theindividual contact members electrically with the common contact.

3. In a multi-position electric switch, the combination of a first andsecond cooperating relatively movable contact carriers of insulatingmaterial; a common contact; supporting means integral with the commoncontact, the second contact carrier being molded to the supportingmeans, a plurality of contact members arranged in a row and fixedlysecured to one side along the outer edge of the first contact carrier,each of the contact members being provided with a laterally disposedcurved portion, the edges of the curved portion being embedded in thefirst contact carrier to prevent movement of the contact member withrespect to the first contact carrier; a pair of symmetrical jawsintegrally secured to each of the contact members; and a rivet fixedlysecuring each of the contact members to the first contact carrier, therivet being received by an opening provided in the contact memberintermediate the symmetrical jaws and the curved portion to permit freemovement of the symmetrical jaws upon selective engagement with thecommon contact, the common contact lying in a plane interposed betweeneach of the pair of symmetrical jaws and moving relative to the firstcarrier in a path to be selectively engageable with the symmetrical jawsof each of the contact members as the switch is actuated to con- 7 nectthe individual contact members electrically with the common contact.

4. In a multi-position electric switch, the combination of a first andsecond cooperating relatively movable contact carriers of insulatingmaterial; a plurality of contact members arranged in a row and fixedlysecured to one side along the outer edge of the first contact carrier,each of the contact members being provided with a laterally disposedcurved portion, the edges of the curved portion being embedded in thefirst contact carrier to prevent movement of the contact member withrespect to the first contact carrier; a pair of symmetrical jawsintegrally secured to each of the contact members; a common contact; andsupporting means integral with the common contact, the second contactcarrier being molded to the supporting means, the common contact lyingin a plane interposed between each of the pair of symmetrical jaws andmoving relative to the first carrier in a path to be selectivelyengageable with the symmetrical jaws of each of the contact members asthe switch is actuated to connect the individual contact memberselectrically with the common contact.

5. A multi-position electric switch comprising:

a stator of insulating material having a thick outer peripheral sectionand a thin inner peripheral section;

a plurality of abutments on the outer peripheral section;

a plurality of contacts, each contact being located between twoabutments;

a rivet attaching each of the contacts to the outer peripheral sectionof the stator;

a curved section on each contact adjacent the outer periphery of thestator resiliently engaging the abutments on each side of the contact toalign the contact and resist rotation of the contact around the rivet;and

a rotor rotatably supported by the stator, comprising:

body of insulating material; and a plurality of metal inserts embeddedin the body and extending outwardly therefrom to engage the contactsattached to the stator.

6. A multi-position electric switch comprising:

an annular body of insulating material having a relatively thick outerperipheral section and a substantially thin inner peripheral section;

a plurality of radially extending, equally spaced ribs on at least oneside of the thick outer peripheral section;

a plurality of symmetrical metallic contact members attached to theannular body with each contact member being located between a pair ofthe ribs;

means attaching the contact members to the annular body;

each of the metallic contact members having a curved section locatedadjacent the outer periphery of the annular body, said curved sectionhaving a width initially less than the space between adjacent ribs but awidth greater than the distance between the ribs when flattened, so thatthe edges of the curved section will be forced into engagement with theribs when the contact member is attached to the stator; and

a rotor rotatably supported by the substantially thin inner peripheralsection of the annular body comprising a body of insulating materialhaving a metal contact embedded therein.

7. A multi-position electric switch comprising an annular body ofinsulating material having a relatively thick outer peripheral sectionand a thin inner peripheral portion;

a plurality of abutments on the thick outer peripheral section;

a plurality of contact members with each member being located between apair of abutments;

means attaching the contact members to the stator;

each contact member being characterized by two oppositely curvedsections extending transverse the contact member with one curved sectionengaging the abutment on each side of the contact member to resistrotation of the contact member around the attaching means; and a contactblade engageable with the contact members.

8. A stator for a multi-position electric switch comprising:

a body of insulating material equipped with a plurality of abutments,said abutments being so constructed and arranged that the distancebetween the abutments is a minimum along the outer periphery of thebody;

a plurality of symmetrical contacts attached to the body with eachcontact being located between two abutments;

openings in each of the contacts and in the body between each pair ofabutments where a contact is located;

holding means extending through the openings in the contacts and thebody of insulating material securely attaching the contacts to the body;

said contacts being characterized by the fact that they are providedwith two oppositely curved transverse sections adjacent the outerperiphery of the body, the curved sections initially having a width lessthan the minimum distance between the abutments but greater than theminimum distance when they are fiat, so that when attached to the bodyby the holding means, the curved transversed sections will be flattenedto the extent that at least one curved transversed section willresiliently engage the abutments on each side to thereby accuratelyalign the contact with respect to the abutments and to resist therotation of the contact around the holding means.

9. A multi-position electric switch comprising, in combination, a statorand a rotor;

said stator comprising a body of insulating material having a relativelythin inner section having a central opening therein, a relatively thickperipheral section, and a plurality of stationary contacts attached tothe peripheral section;

said rotor comprising two annular bodies of insulating material; a metalmember embedded in one annular body and extending outwardly from theperipheral edge thereof in the plane of the stationary contacts; each ofthe annular bodies having a diameter larger than the central opening inthe stator and an end section of reduced diameter which extends into thecentral opening in the stator, and means attaching the two annularbodies together so that both annular bodies will be rotatably supportedby the inner section of the stator.

lit). A multi-position electric switch comprising:

an annular stator body of non-conductive material having a relativelythick outer peripheral section and a relatively thin inner peripheralsection;

a plurality of U-shaped metallic contact members;

means attaching the U-shaped metallic contact members to the thick outerouter peripheral section of the annular stator body;

each of the metallic contact members having an initially curved sectionlocated adjacent the outer periphery of the stator body, said curvedsection being curved to the extent that only the edges of the curvedsection engage the stator body so that when the contact members areattached to the stator body the curved section will be partiallyflattened and the edges will be embedded in the stator body;

a rotor rotatably supported by the stator body;

said rotor comprising two sections rotatably mounted on opposite sidesof the relatively thin inner peripheral section; each of the sections ofthe rotor being provided with a circumferential groove engaging the2,594,111 4/52 Albrecht 2001 67 X edge of the thin inner peripheralsection of the all- 2,631,211 3/53 Klay. nular stator body; and2,828,393 3/58 Wingard 20011 a metal contact molded in the rotor andarranged to 2 900 462 8/59 Th t 1 200 11 engage the contact members onthe stator body. 5 2,949,511 8/60 Glueckstein et 1 20 11 ReferencesCited by the Examiner x lm lson UNITED STATES PATENTS 2,989,710 6/61Gelzer et a1. 2,210,842 8/40 Schellenger 200-11 2,554,724 5/51 Williams200-11 10 BERNARD A. GILHEANY, Primary Examiner.

5. A MULTI-POSITION ELECTRIC SWITCH COMPRISING: A STATOR OF INSULATINGMATERIAL HAVING A THICK OUTER PERIPHERAL SECTION AND A THIN INNERPERIPHERAL SECTION; A PLURALITY OF ABUTMENTS ON THE OUTER PERIPHERALSECTION; A PLURALITY OF CONTACTS, EACH CONTACT BEING LOCATED BETWEEN TWOABUTMENTS; A RIVET ATTACHING EACH OF THE CONTACTS TO THE OUTERPERIPHERAL SECTION OF THE STATOR; A CURVED SECTION ON EACH CONTACTADJACENT THE OUTER PERIPHERY OF THE STATOR RESILIENTLY ENGAGING THEABUT-